Diagnostic accuracy of two software modalities for detection of caries lesions in digital radiographs from four dental systems.

Dentomaxillofac Radiol. 2006 Mar;35(2):78-82

Authors: Hintze H

OBJECTIVE: To compare the caries diagnostic accuracy of two software modalities used in the assessment of digital radiographs obtained with four different dental systems, and to evaluate whether the software used for image assessment influenced the mutual comparison of those four dental systems relating to their caries diagnostic accuracy. METHODS: Under in vitro and standardized conditions 122 teeth (with 228 unrestored approximal and 99 occlusal surfaces) were radiographed in blocks of 3 test teeth and 2 non-test teeth using two storage phosphor plate systems: Digora (Soredex, Helsinki, Finland) and DenOptix (Gendex, Dentsply, Milan, Italy) and two charge coupled device (CCD)-based sensor systems: Dixi (Planmeca, Helsinki, Finland) and Sidexis (Sirona, Bensheim, Germany). The images were displayed and examined in two software modalities: their own dedicated software and a general software. Three observers examined all images for the presence of approximal enamel and dentine and occlusal dentine caries lesions using a 5-point confidence scale. The true presence of caries was validated by ground section histology. The diagnostic accuracy of the software modalities was expressed as ROC curve areas (A(z)) and differences between modalities were tested by paired t-test. Comparison of systems was analysed by post hoc t-test. RESULTS: Results of approximal and occlusal surfaces assessed together revealed nearly identical mean A(z) with the two software modalities on images obtained with the Digora (A(z)=0.71) and DenOptix (A(z)=0.72) systems. On Dixi images the mean A(z) was 0.75 using the system's own software and 0.73 using the general software. On Sidexis images the corresponding mean A(z)s were 0.79 and 0.75. None of those differences were significant. CONCLUSION: No significant difference in caries diagnostic accuracy was found between two software modalities used for examination of digital radiographs obtained with four different digital systems, and the software modality did not influence the mutual rank of the four systems relating to their diagnostic accuracy.

PMID: 16549433 [PubMed - indexed for MEDLINE]

Performance evaluation and testing of digital intra-oral radiographic systems.

Radiat Prot Dosimetry. 2005;117(1-3):313-7

Authors: Doyle P, Finney L

Four digital intra-oral radiographic systems were tested and evaluated; three charge-coupled device (CCD) based systems from RVG, Visualix and Sidexis and a photostimulable phosphor (PSP) system from DenOptix. Image quality was assessed using three purpose-built phantoms to measure uniformity, low contrast detail detectability and signal-to-noise ratio (SNR). Limiting resolution was measured using a 20 lp mm(-1) bar pattern. Radiation output inaccuracies caused difficulties in achieving optimum doses for CCD systems. However, the accuracy was improved by using K-edge filters. SNR measurements proved to be a useful tool in assessing system performance. Each system has specific attributes: resolution was highest for the RVG system, the Visualix system measured the highest SNR and the lowest exposure settings were on the Sidexis system. Test methods and phantoms developed are suitable for acceptance testing and commissioning digital dental X-ray systems and for programming each system to produce an optimum level of image quality.

PMID: 16461488 [PubMed - indexed for MEDLINE]

Comparison of direct digital and conventional imaging with Ekta Speed Plus and INSIGHT films for the detection of approximal caries.

Am J Dent. 2005 Aug;18(4):241-4

Authors: de Araujo EA, Castilho JC, Medici Filho E, de Moraes ME

PURPOSE: To evaluate the accuracy of approximal caries detection comparing enhanced and unenhanced Sidexis CCD-based digital image with Ektaspeed Plus and INSIGHT films. METHODS: Fifty-two extracted premolars were imaged under identical standardized geometric and exposure conditions. Four observers, using five points confidence scale, rated 104 approximal surfaces for the presence or absence of carious lesions by means of four image modalities: (1) observer enhanced; (2) unenhanced Sidexis displays; (3) E speed films and (4) F speed film. Histologic sections served as validating criterion for the presence and depth of carious lesions. Diagnostic accuracy was measured as the area beneath the ROC curve. RESULTS: Mean ROC (receiver operating characteristic) curve areas for approximal surfaces were 0.865 (E speed), 0.856 (F speed), 0.816 (unenhanced Sidexis) and 0.776 (observer enhanced). There were no significant differences between unenhanced digital Sidexis and films. Observer enhanced Sidexis images exhibited a statistically significant lower diagnostic accuracy than the film images for two of the observers.

PMID: 16296430 [PubMed - indexed for MEDLINE]

Proximal caries detection: Sirona Sidexis versus Kodak Ektaspeed Plus.

Gen Dent. 2005 Jan-Feb;53(1):43-8

Authors: Khan EA, Tyndall DA, Ludlow JB, Caplan D

This study compared the accuracy of intraoral film and a charge-coupled device (CCD) receptor for proximal caries detection. Four observers evaluated images of the proximal surfaces of 40 extracted posterior teeth. The presence or absence of caries was scored using a five-point confidence scale. The actual status of each surface was determined from ground section histology. Responses were evaluated by means of receiver operating characteristic (ROC) analysis. Areas under ROC curves (Az) were assessed through a paired t-test. The performance of the CCD-based intraoral sensor was not different statistically from Ektaspeed Plus film in detecting proximal caries.

PMID: 15779222 [PubMed - indexed for MEDLINE]

Grey-scale reversed radiographic display in the detection of approximal caries.

J Dent. 2005 Jan;33(1):65-71

Authors: Haak R, Wicht MJ

OBJECTIVES: Purpose of this study was to determine the influence of grey-scale reversal of digital radiographic images on the detection of proximal caries. METHODS: Five observers assessed digital bitewing radiographs (Sidexis((R)), Sirona) of 320 unrestored surfaces of extracted posterior teeth embedded in 20 models, simulating pairing of maxillary and mandibular arches, using a six-category caries rating scale. Images were displayed in normal [N] and inverse [IN] mode at different image sizes (display ratio: 1:1, 1:2, 1:7) on a cathode-ray tube monitor (Nokia 446 XS) and a TFT display (Panasonic LC 50 S). Validation standard was defined as histological lesion depth. Validity was expressed as areas under receiver operating characteristic curves (AUC) calculated for two levels of histological caries penetration: presence of caries and presence of a dentine lesion. The factors 'inverse display', 'image size on-screen' 'display type' and 'disease cut-off' were analysed by repeated measures ANOVA. RESULTS: Inverse image display significantly influenced the diagnostic validity (P=0.014), but a reduced accuracy was only seen at the lowest image size (AUC (SE): [N] 0.64 (0.02); [IN] 0.62 (0.02)). At the validation threshold 'dentine caries' approximal caries detection deteriorated when using grey-scale reversal (AUC (SE): [N] 0.71 (0.02); [IN] 0.69 (0.02)). CONCLUSIONS: In conclusion, grey-scale reversal of digital radiographs did not optimise approximal caries detection and aggravated the detectability of dentinal lesions.

PMID: 15652170 [PubMed - indexed for MEDLINE]

Evaluation of endodontic files in digital radiographs before and after employing three image processing algorithms.

Dentomaxillofac Radiol. 2004 Jan;33(1):6-11

Authors: Li G, Sanderink GC, Welander U, McDavid WD, Näsström K

OBJECTIVES: Two digital image processing algorithms, one aimed at correction for exponential attenuation and one at correction for visual response, have been developed. The aims of the present study were to test whether digital radiographs processed with these algorithms improve determination of the length of endodontic files and whether such processed radiographs are comparable with the radiographs processed with a default image processing method employed by one commercially available digital intraoral system. METHODS: A dried human skull embedded in an acrylic compound was used for exposing radiographs of the upper and lower premolars and molars with endodontic files (Kerr files size 10 and size 15) positioned to the full length of the roots or 1.5 mm short of it. Radiographs were then processed in three sets. In one set, the radiographs were processed to compensate for exponential attenuation and the response of the human visual system. In the second, the radiographs were processed with the same compensation but with an additional shift in grey levels so that the output luminance in dentin at root tips corresponds to the mean of the luminance range of a computer monitor. In the third, the radiographs were processed with the default processing method in the Sidexis program. Ten viewers evaluated all radiographs. Receiver operating characteristic (ROC) curves were obtained and areas under the curves were calculated. RESULTS: For file size 10, ROC curves for processed radiographs were higher than that for originals, while for file size 15, ROC curves for processed and original radiographs were close to each other. Significant differences were found between processed and original radiographs regarding areas under ROC curves for file size 10 but not between the differently processed radiographs. For file size 15, no significant differences were found. CONCLUSION: Radiographs processed to correct for attenuation and visual response may improve determination of the length of thin endodontic files. Such processed radiographs are comparable with the radiographs processed with the default processing method in the Sidexis program.

PMID: 15140815 [PubMed - indexed for MEDLINE]

Integration of multiple direct digital imaging sources in a picture archiving and communication system (PACS).

Dentomaxillofac Radiol. 2003 Sep;32(5):337-42

Authors: Gotfredsen E, Wenzel A

OBJECTIVES: The aim of this report was to describe a flexible picture archiving and communication system (PACS) able to handle and communicate digital image data from various radiography systems and other sources. METHODS: The radiographic image is acquired using the vendor's own software. Following image capture, a "request for update" message (appending a record to an Access database) activates our PACS engine, "DigiMerge". Images from sources with no patient-related organizing software, e.g. TWAIN-compatible scanners and digital cameras, are handled by a self-developed program, "MedCom-T". DigiMerge generates and maintains one database based on all manufacturers' databases (software: VixWin 2000, Digora for Windows, Dimaxis Pro, Sidexis, CDR DICOM for Windows, Trophy for Windows). This database contains patient information, image information and image path. The program "DigiView" searches a patient and displays patient and image data from the database generated by DigiMerge. With DigiView, images can be viewed at any workstation in the dental school, but only temporary changes can be made (contrast, brightness, etc.) and no image can be deleted. RESULTS: The PACS is currently installed on 86 workstations. Statistics collected by DigiMerge reveal that approximately 2000 new digital images are recorded each month, half of which are radiographs and the other half are clinical photographs. Statistics collected by DigiView reveal that 500-800 digital images are opened per week. CONCLUSIONS: The self-developed PACS is able to manage images from a range of digital modalities each providing its own image data format.

PMID: 14709611 [PubMed - indexed for MEDLINE]

Relationship between histological and radiographic caries lesion depth measured in images from four digital radiography systems.

Caries Res. 2004 Jan-Feb;38(1):34-8

Authors: Jacobsen JH, Hansen B, Wenzel A, Hintze H

The aim of this study was to compare the accuracy of approximal caries lesion depth measurements in radiographs from four digital systems. Two CCD-based sensors, Dixi (Planmeca) and Sidexis (Sirona), and two phosphor plate systems, Digora (Soredex) and DenOptix (Gendex), were used to record radiographs of 177 extracted human teeth. Sixty-four radiographically visible lesions were selected and measured by 4 observers in the digital radiographs and in digital photographs of histological sections of the teeth. The gold standard (true measure) was defined as the mean of the 4 observers' measurements on the histological sections. Two untrained observers underestimated general lesion depth in all the radiographic systems while each of 2 trained observers underestimated the depth in one of the systems. Analysis of variance revealed that Digora images resulted overall in the smallest underestimation, followed by Dixi, DenOptix and Sidexis. The differences between Digora and Sidexis and between Dixi and Sidexis were statistically significant (p < 0.05). Analysis of variance using the regression coefficient as the test variable demonstrated that the coefficients differed between DenOptix and the remaining systems (p < 0.05) while there were no significant differences between these (p > 0.05). It can be concluded that radiographs obtained with the Dixi and Digora systems were more accurate than Sidexis and DenOptix images for measurement of caries lesion depth. Still, a high probability exists that the individual lesion measurement is either overestimated or underestimated compared to the true lesion depth.

PMID: 14684975 [PubMed - indexed for MEDLINE]

A comparison of two intraoral CCD sensor systems in terms of image quality and interobserver agreement.

Int J Comput Dent. 2003 Apr;6(2):141-50

Authors: Schulze D, Rother UJ, Fuhrmann AW, Tietke M

PURPOSE: Two intraoral CCD sensor systems were compared with respect to image quality and interobserver agreement. MATERIALS AND METHODS: Forty intraoral images from each of the sensors (Trophy RVG5, Sirona Sidexis) were examined by 4 observers in terms of anatomical landmarks and general image quality. The images were divided into 2 groups--filtered and unfiltered. Kappa values for interobserver agreement were calculated for all assessed points. RESULTS: The Trophy sensor showed better image quality in the filtered group, and the Sirona sensor demonstrated good image quality in the unfiltered group. Moderate to substantial interobserver agreement was achieved. The use of filters increased edge artefacts. Sensor specific artefacts in the Trophy system were observed.

PMID: 14552151 [PubMed - indexed for MEDLINE]

Influence of displayed image size on radiographic detection of approximal caries.

Dentomaxillofac Radiol. 2003 Jul;32(4):242-6

Authors: Haak R, Wicht MJ, Nowak G, Hellmich M

OBJECTIVES: To evaluate the validity of approximal caries detection on digital bitewing radiographs displayed at different image sizes on either a cathode ray tube (CRT) monitor or a thin film transistor (TFT) monitor. METHODS: Five observers assessed digital radiographs of a charge-coupled device (CCD)-based sensor system (Sidexis) of 160 unrestored premolars and molars for approximal caries using a six category caries rating scale. Images were displayed at ratios of 1:1, 1:2 and 1:7 on a CRT monitor (Nokia 446 XS) and a TFT display (Panasonic LC 50S). Histological assessments of serial sections were used as the validation standard. Diagnostic accuracy was expressed as area under the receiver operating characteristic (ROC) curve (AUC) and was calculated at two levels of caries penetration: presence of caries (I) and presence of a lesion in the dentine (II). The influence of the factors "monitor type", "image size" and "validation threshold" were analysed with repeated measures analysis of variance. RESULTS: The ROC curve areas for approximal caries detection at both histological penetration levels were not influenced by the type of monitor display, whereas image size had a significant impact (P<0.01). AUCs for image size 1:7 (I, 0.62; II, 0.65) were smaller compared with ratios of 1:1 and 1:2 (P<0.01). No differences were observed between image size ratios 1:1 (I, 0.69; II, 0.74) and 1:2 (I, 0.68; II, 0.73). CONCLUSIONS: In this study, the type of monitor did not influence approximal caries detection on digital radiographs. Image sizes with a display ratio of 1:1 and 1:2 resulted in better diagnostic validity than those with a ratio of 1:7.

PMID: 13679355 [PubMed - indexed for MEDLINE]

Root fracture detection on digital images: effect of the zoom function.

Dent Traumatol. 2003 Jun;19(3):154-9

Authors: Kositbowornchai S, Sikram S, Nuansakul R, Thinkhamrop B

To assess the accuracy of root fracture detection at various levels of image magnification. METHODS: Extracted single-rooted human teeth (100 non-fractured and 101 fractured) were mounted singly in wax blocks and a charge-coupled device (CCD)-based digital Sidexis imaging system was used to take images using the paralleling technique. Image sizes 1 : 1, 2 : 1, and 1 : 2 were prepared for each tooth. All 603 images were examined randomly and interpreted by an experienced radiologist unaware of which images were of fractured roots. The degree of agreement between image interpretation and the actual condition was estimated using a kappa statistic. A modified goodness-of-fit chi2-test was used to assess the significance of the difference between the three image sizes. The sensitivity, specificity, predictive value, and likelihood ratio were used to evaluate the accuracy of root fracture detection at each level of magnification. The degree of agreement between pairs of viewing conditions was also calculated using a kappa statistic. RESULTS: There was substantial agreement between image interpretation and the actual condition for both the 1 : 1 and 1 : 2 image sizes but only moderate agreement for the 2 : 1 size. The kappa values (and 95% CIs) were 0.65 (0.51-0.79), 0.63 (0.49-0.77), and 0.58 (0.44-0.72), respectively. The differences were not statistically significant (P-value = 0.79). The sensitivity (95% CI) of the image magnification ranged between 79.0% (70.0-87.5%) and 81.0% (72.2-87.5%). The 1 : 1 image size gave the highest specificity of 86.1% (95% CI: 78.1-91.6%). The positive predictive values (95% CI) of the 1 : 1, 1 : 2, and 2 : 1 images sizes were 84.9% (76.3-90.8%), 81.8% (73.1-88.2%), and 77.9% (69.0-84.8%), respectively. The negative predictive values (95% CI) were 80.6% (72.1-86.9%), 81.4% (73.8-88.9%), and 80.4% (71.4-87.1%) for the 1 : 1, 1 : 2, and 2 : 1 image sizes, respectively. The likelihood ratios of the positive test (95% CI) were 5.70 (3.47-9.36), 4.55 (3.00-6.98), and 3.56 (2.45-5,16) for the 1 : 1, 1 : 2, and 2 : 1 image sizes, respectively. The likelihood ratios of the negative test (95% CI) were 0.24 (0.17-0.36), 0.23 (0.15-0.35), and 0.25 (0.16-0.37) for the 1 : 1, 1 : 2, and 2 : 1 image sizes, respectively. The reliability between pairs of viewing conditions was substantial. The kappa statistics (95% CI) was 0.80 (0.72-0.88), 0.73 (0.64-0.83), and 0.77 (0.68-0.86), respectively. CONCLUSION: In this in vitro study, the three digital magnifications used did not affect the detection of root fractures.

PMID: 12752537 [PubMed - indexed for MEDLINE]

Influence of the validation method on diagnostic accuracy for caries. A comparison of six digital and two conventional radiographic systems.

Dentomaxillofac Radiol. 2002 Jan;31(1):44-9

Authors: Hintze H, Wenzel A

OBJECTIVE: To evaluate the influence of the validation method on the diagnostic accuracy and the relative comparison of eight radiographic systems for caries detection. METHODS: Three hundred and thirty-eight approximal and 145 occlusal surfaces were radiographed under standardised conditions using six CCD-based sensor systems: MPDx (Dental/Medical Diagnostic Systems Inc., Woodland Hills, CA, USA), Dixi (Planmeca, Helsinki, Finland), Sidexis (Sirona, Bensheim, Germany), RVG(old) (Trophy, Paris, France, 1994 model), RVG(new) (Trophy, Paris, France, 2000 model) and Visualix (Gendex, Milan, Italy) and two film systems: Ektaspeed Plus and Insight (Eastman Kodak, Rochester, NY, USA). Four observers examined the radiographs for approximal and occlusal caries using a five-point confidence scale. The presence of caries was validated histologically and radiographically. Diagnostic accuracy was evaluated using ROC curve areas (A(z)). RESULTS: For both approximal and occlusal caries the mean A(z) of the eight radiographic systems was significantly higher using radiographic than histological validation (P<0.001). Using histological validation for approximal caries, Dixi (A(z)=0.71) and Ektaspeed Plus (A(z)=0.7) were not significantly different, but Dixi was significantly more accurate than the other digital systems and the Insight film. Using radiographic validation for approximal caries, Ektaspeed Plus (A(z)=0.87) was significantly more accurate than Dixi (A(z)=0.82). Dixi was significantly more accurate than MPDx (A(z)=0.74), RVG(old) (A(z)=0.77), RVG(new) (A(z)=0.77) and Visualix (A(z)=0.76). Corresponding variations were found for occlusal caries depending on the validation method. Using histological validation, MPDx (A(z)=0.76) was significantly less accurate than Dixi (A(z)=0.81), Sidexis (A(z)=0.8), Ektaspeed Plus (A(z)=0.82) and Insight (A(z)=0.81). Using radiographic validation, MPDx (A(z)=0.83) was also significantly less accurate than RVG(old) (A(z)=0.89) and RVG(new) (A(z)=0.9). CONCLUSION: A(z) obtained from radiographic validation was significantly higher than A(z) obtained from histological validation. Comparison of the diagnostic efficacy for caries of the eight radiographic systems was strongly influenced by the validation method. DOI: 10.1038/sj/dmfr/4600645

PMID: 11803388 [PubMed - indexed for MEDLINE]

How to improve digital dental radiograph reproducibility: an individualized technique.

Int J Comput Dent. 2001 Apr;4(2):117-24

Authors: Muratore F, Tripodi D, Tet&#xE9; S, de Fazio P, Festa F

Today, the advantages of the use of digital dental radiography as a valid alternative to conventional techniques are well known. In clinical dental practice, it can be useful to realize intraoral dental x-rays that can be compared, even after some years. The use of a conventional XCP instrument with the "long cone" technique helps to limit image distortion, but the comparison is poor. Moreover, in digital radiography, obtaining almost identical images is essential to superimpose them with dedicated software. The aim of the present work was to obtain fully superimposable and reproducible intraoral digital images through the use of an individual resin positioner. The laboratory phases are all described to create a system that enables exact placement of the digital sensor SIDEXIS (Sirona, Germany) in the mouth of the patient. The authors present a case report where the described technique is applied in the orthodontic field to evaluate molar distalization with a fixed appliance.

PMID: 11692661 [PubMed - indexed for MEDLINE]

Effects of different exposure values on diagnostic accuracy of digital images.

Quintessence Int. 2000 Apr;31(4):257-60

Authors: Pfeiffer P, Schmage P, Nergiz I, Platzer U

OBJECTIVE: The aim of this in vitro study was to compare the effects of different exposure values on the image clarity of 3 digital radiographic systems and 1 conventional direct-exposure emulsion x-ray film. METHOD AND MATERIALS: Three digital radiographic systems, Digora, RVG, and Sidexis, were compared with the conventional dental x-ray film, Ektaspeed Plus. A medullary bone fragment and human teeth were radiographed with varying voltage, exposure time, and focus-receptor distance. Clinical criteria to evaluate image clarity were detail resolution, sharpness, contrast resolution, and artifacts of the different tooth and jaw structures. RESULTS: The optimal exposure times for digital imaging varied between 0.02 and 0.13 seconds and depended on the objects and the imaging systems. Optimal resolution was obtained when a voltage of 60 kV was used. The focus-receptor distance of 33 to 40 cm resulted in the best contrast and sharpness. Digital images did not always provide the detail resolution or sharpness achieved by conventional radiographs. CONCLUSION: The recommended exposure time for digital images amounted to approximately half the time needed for conventional film. Digital images had to be modified by adjusting the contrast and brightness to optimize the visibility of the areas to be diagnosed.

PMID: 11203933 [PubMed - indexed for MEDLINE]

Radiographic detection of approximal caries: a comparison of dental films and digital imaging systems.

Dentomaxillofac Radiol. 2000 Sep;29(5):312-8

Authors: Syriopoulos K, Sanderink GC, Velders XL, van der Stelt PF

OBJECTIVES: To compare the diagnostic accuracy for the detection of approximal caries of two dental X-ray films, two CCD-based digital systems and two storage phosphor (SP) digital systems. METHODS: Fifty-six surfaces in 56 extracted unrestored premolars were radiographed under standardised conditions using two E-speed dental film, Ektaspeed Plus (Eastman Kodak Co, Rochester, NY, USA) and Dentus M2 Comfort (Agfa-Gevaert, Mortsel, Belgium), two CCD systems, Sidexis (Sirona, Bensheim, Germany) and Visualix (Gendex, Milan, Italy) and two SP systems, Digora (Soredex, Helsinki, Finland) and DenOptix (Gendex, Milano, Italy). The images were assessed by eight observers (four radiologists and four general practitioners). True caries depth was determined by histological examination. True caries depth was subtracted from the values given by the observers and an analysis of variance was performed. The null hypothesis was rejected when P < 0.05. RESULTS: No significant differences were found in diagnostic accuracy with the two dental films and the Sidexis and Digora systems. The depth of the lesion significantly affected observer performance. Caries depth was underestimated. Radiologists performed significantly better than general practitioners whatever the recording system. CONCLUSION: The diagnostic accuracy of digital systems is comparable with that of dental films. The ability of dentists to recognise caries correctly is the main factor contributing to variation in radiographic diagnosis and not the imaging modality.

PMID: 10980568 [PubMed - indexed for MEDLINE]

Discrimination between restorative dental materials by their radiopacity measured in film radiographs and digital images.

J Forensic Odontostomatol. 1998 Jun;16(1):8-13

Authors: Wenzel A, Hintze H, H&#xF8;rsted-Bindslev P

The aim of this study was to investigate the possibility of differentiating between various dental restorative materials by means of their radiopacity. Ten extracted molars and ten canines/anterior teeth were selected for the study. In the molar group a class II cavity and in the canines/anterior teeth group a class III cavity were cut by airrotor. The cavities were coated with vaseline before filling with five molar- and three anterior tooth restorative materials in the following sequence: for molars: amalgam, light-cured composite, glass ionomer cement, reinforced glass ionomer cement and light-cured composite. After each filling sequence radiographs were taken of the teeth on conventional film (Ektaspeed Plus) and by two digital systems: a storage phosphor plate (Digora) and a ccd-based sensor (Sidexis). Density was measured in the films with a densitometer in three areas of "air", in three areas of the class II fillings and one area of the class III fillings. The same areas were measured in the digital images where the program calculated automatically the mean grey shade values. The density values obtained from the filling areas were taken as a proportion of the values obtained from the areas of "air". Statistically significant differences in material density when related to "air" density (Wilcoxon's test) were observed between all materials in film (p < 0.01 for molars and p < 0.02 for canines/anterior teeth). For Digora only half of the materials differed significantly which was also the case for the Sidexis system (none of the CF materials were significantly different). In conclusion, the molar filling materials could be distinguished with a high probability in film while the two digital systems were less reliable. The results may be useful in forensic dentistry.

PMID: 9922755 [PubMed - indexed for MEDLINE]

An evaluation of periapical radiography with a charge-coupled device.

Dentomaxillofac Radiol. 1998 Mar;27(2):97-101

Authors: Versteeg CH, Sanderink GC, van Ginkel FC, van der Stelt PF

OBJECTIVES: To compare the standards of periapical radiography with a CCD-image receptor with film. METHODS: Three radiography technicians exposed a total of fifty teeth from all areas of the jaws using either size 1 or size 2 film and the Sidexis (Siemens, Bensheim, Germany) direct digital dental radiography system with the appropriate film holders. Image quality was assessed by two dental radiologists for nine individual criteria and overall, on a three-point scale. RESULTS: There was a significant difference between film and sensor exposures (P < 0.014). Six per cent of dental films required retakes compared with 28% with the sensor. CONCLUSION: Periapical radiography with a CCD sensor leads to more errors and thus more retakes than conventional film.

PMID: 9656874 [PubMed - indexed for MEDLINE]

Periodontitis detection efficacy of film and digital images.

Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1998 May;85(5):608-12

Authors: Nair MK, Ludlow JB, Tyndall DA, Platin E, Denton G

OBJECTIVE: The objective of this study was to evaluate the accuracy of alveolar crestal bone detection in a comparison of unenhanced and enhanced Sidexis (Siemens Medical Systems, Inc., Bensheim, Germany) digital images with Ektaspeed Plus (Eastman Kodak, Rochester, N.Y.) films by means of receiver operating characteristic analysis. STUDY DESIGN: More than 100 proximal and furcal areas in the anterior and posterior areas of the mandible and maxilla of each of three tissue-equivalent human skull phantoms were imaged with film, direct digital images, and contrast- and brightness-enhanced digital images. Alveolar crest status was assessed by a consensus panel of three experts who used the Delphi method and evaluated information from all of the imaging modalities concurrently. Five observers assessed all images for the presence or absence of crestal bone loss using a five-point confidence scale. Receiver operating characteristic curves were generated, and calculated areas (Az) were analyzed by means of analysis of variance. RESULTS: The expert panel determined that of 106 crestal areas, 48 were disease free and 58 exhibited bone loss greater than 2 mm apical to the cemento-enamel junction. Analysis of variance of observer Az scores showed significant differences among readers (p < 0.001) and among readings (p = 0.027), but not among modalities (p = 0.435). Mean Az values for the different modalities were as follows: Sidexis, 0.70; enhanced Sidexis, 0.71; Ektaspeed Plus films, 0.735. CONCLUSION: The Sidexis digital imaging system was not significantly different from Ektaspeed Plus film for crestal bone evaluation in this in vitro study.

PMID: 9619682 [PubMed - indexed for MEDLINE]

Impact of scale standardization on images of digital radiography systems.

Dentomaxillofac Radiol. 1997 Nov;26(6):337-43

Authors: Versteeg CH, Sanderink GC, Geraets WG, van der Stelt PF

OBJECTIVES: To test the effect of altering image size on diagnostic quality. METHODS: Endodontic files, size 10 and 15 were prepared to full root length and 1.5 mm short, in upper and lower molars and premolars. Digital images of the Sidexis (S) and Visualix/Vixa (V) system were reduced in size to Digora (D) scale, and the D images were enlarged to S scale. ROC analysis was performed and data analysed with MANOVA statistics. RESULTS: Assessment of root canal length with file size 10 was less accurate for the S images reduced in size, compared with the original S images (P < 0.011). All other differences were not significant (P > 0.081). CONCLUSIONS: Relevant diagnostic information may be lost when images are reduced in size. Therefore, for optimal presentation, the smaller images should be enlarged rather than the larger ones reduced.

PMID: 9482009 [PubMed - indexed for MEDLINE]

A comparison of Kodak Ektaspeed Plus film and the Siemens Sidexis digital imaging system for caries detection using receiver operating characteristic analysis.

Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1998 Jan;85(1):113-8

Authors: Tyndall DA, Ludlow JB, Platin E, Nair M

OBJECTIVE: To evaluate the accuracy of proximal caries detection comparing enhanced and unenhanced Siemens Sidexis CCD-based digital images with Ektaspeed Plus films utilizing receiver operating characteristic analysis. STUDY DESIGN: Sixty extracted teeth (24 posterior and 36 anterior) were imaged under identical standardized geometric and exposure conditions. Six observers, using a 5-point confidence scale, rated 120 proximal surfaces for the presence or absence of carious lesions by means of three image modalities: (1) observer enhanced and (2) unenhanced Sidexis displays, and (3) Ektaspeed Plus films. The ground truth was determined by microscopic analysis of ground sections. Receiver operating characteristic curves were generated with calculated areas (AZ) analyzed with analysis of variance for effect of reader, reading, and modality. RESULTS: Analysis of variance demonstrated significant differences among readers, readings and modalities (mean square values of 0.012, 0.005, 0.004, F ratios of 13.604, 5.329, 5.100; p = values of 0.001, 0.043, and 0.030, respectively). Post-hoc paired comparisons of modalities using Tukey's statistic demonstrated that only film and enhanced Sidexis images were different from each other (p = 0.024). AZ scores were 0.7650, 0.7499, and 0.8008 respectively, for unenhanced Sidexis, enhanced Sidexis, and Ektaspeed Plus film. CONCLUSION: Unenhanced digital Sidexis images were equivalent to film for the detection of proximal caries in this in vitro study. Observer enhanced Sidexis images exhibited a statistically significant lower diagnostic accuracy than the unenhanced digital and film images.

PMID: 9474625 [PubMed - indexed for MEDLINE]

Dose reduction of two digital sensor systems measuring file lengths.

Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1996 May;81(5):607-12

Authors: Velders XL, Sanderink GC, van der Stelt PF

OBJECTIVE. The aim of this study was to determine the effect of dose reduction on the image quality of two sensor systems with automatic greyscale adjustment. STUDY DESIGN. Two digital sensor systems, Sidexis (Siemens, Bensheim, Germany) and Digora (Soredex, Helsinki, Finland), were tested. The image quality of the systems was determined by comparing lengths of endodontic files (025, 020, 015, and 010 files) and a premolar root in the digital images with lengths on conventional radiographic films. For the experiments the exposure was changed to 100%, 50%, 25%, 12.5%, 6.25%, and 3.125% of that for Ektaspeed films. RESULTS. The lengths of 025 and 020 files and the premolar root in the digital images were comparable with the lengths on films even if the exposure was reduced to 6% of that used for Ektaspeed films. The lengths of 015 files reduced as the exposure was reduced. The lengths of 010 files were significantly shorter than the lengths on films. CONCLUSIONS. With the systems tested, a dose reduction of approximately 95% compared with Ektaspeed films is possible to determine the lengths of a premolar root and 025 and 020 files. For thinner objects a dose reduction is questionable.

PMID: 8734712 [PubMed - indexed for MEDLINE]